If there is one owner owning different childcare centres and if that is okay for the audience to know that all four are connected if there is no legal or any other issue surrounding that, then the best option would be to create one common platform say:
oliverchildcare.com and promote all four with different names through same channel.
like oliverchildcare.com/centres/centre1 , oliverchildcare.com/centres/centre2 . . .
cross promoting different centres would have its own advantages attached with it, as per customer experience as well as SEO.
If you can lay your product like above, nothing like it.
Then if you want to promote a service, you just need to create one common source and can add which centres provide this particular service at what timings.
But if you are putting common content across all 4 channels and want all of them to index and rank, it would be a very tedious task and might end up with none of them indexing.
But if you can go ahead and give one of them wightage, then there are multiple ways of doing so, one of them being putting canonical from all others to one primary domain.
I would recommend creating a common one and promoting all there, if this belongs to one common client/entity/organisation and is more of multiple centres for same type of activity rather than different services all together